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Cert III Horticulture study materials
Cert III Horticulture study resources

Cert III Horticulture practice questions

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Question 1Workplace safety and environmental sustainability in horticulture

Under Australian work health and safety law, what is the primary duty of a person conducting a business or undertaking (PCBU) in a horticultural workplace?

  1. Provide personal protective equipment only when workers request it
  2. Delegate all safety responsibilities to the most senior field hand
  3. Ensure the health and safety of workers and others affected by the work, so far as reasonably practicable Correct answer.
  4. Guarantee that no worker is ever injured on the property

Explanation

WHS legislation places a primary duty of care on the PCBU to protect workers and other persons from harm so far as is reasonably practicable. This duty covers hazards, training, supervision and safe systems of work, and it cannot be fully delegated away.

Question 2Workplace safety and environmental sustainability in horticulture

In the hierarchy of control, which measure ranks highest for managing a hazard?

  1. Administrative controls such as rotation and signage
  2. Providing training and procedures
  3. Using personal protective equipment
  4. Eliminating the hazard from the workplace Correct answer.

Explanation

The hierarchy of control ranks elimination first because removing the hazard entirely prevents exposure. Lower-order measures such as administration and PPE rely on human behaviour and are less reliable.

Question 3Workplace safety and environmental sustainability in horticulture

A worker is about to apply a herbicide and reads the safety data sheet (SDS). What information does an SDS provide?

  1. The recommended application rate for every crop grown in Australia
  2. The hazard properties, safe handling and first aid measures for the chemical Correct answer.
  3. The expiry date of the product batch only
  4. The retail price and supplier discount terms

Explanation

An SDS summarises the hazards of a chemical and gives guidance on safe handling, storage, PPE, spill response and first aid. It is a key reference before using any hazardous substance.

Question 4Workplace safety and environmental sustainability in horticulture

Which item of personal protective equipment is most important when operating a brush cutter to reduce injury from thrown debris?

  1. Face shield and eye protection Correct answer.
  2. Cotton gloves
  3. Steel-capped boots
  4. A high-visibility vest

Explanation

Brush cutters throw stones and plant material at high speed, so eye and face protection is critical to prevent serious eye injury. Boots and high-visibility clothing are useful but do not shield the face.

Question 5Workplace safety and environmental sustainability in horticulture

What is the correct immediate action when a small petrol spill occurs while refuelling a mower?

  1. Wash the fuel into the nearest stormwater drain
  2. Cover the spill with soil and continue refuelling
  3. Stop refuelling, contain the spill with absorbent material and dispose of it correctly Correct answer.
  4. Ignore it because petrol evaporates quickly

Explanation

Spills must be stopped at the source, contained with absorbent material and the waste disposed of through an appropriate waste stream. Preventing fuel from reaching drains or soil protects waterways and groundwater.

Question 6Workplace safety and environmental sustainability in horticulture

What does the term 'environmental sustainability' most accurately mean in a horticultural business?

  1. Avoiding all use of machinery on site
  2. Maximising short-term production regardless of resource use
  3. Using only organic fertilisers on all crops
  4. Meeting present needs while protecting resources and ecosystems for the future Correct answer.

Explanation

Sustainability balances current production needs with protecting soil, water, biodiversity and resources for future use. It is a broad principle, not a single practice such as avoiding machinery or using only organic inputs.

Question 7Workplace safety and environmental sustainability in horticulture

Why is it important to report a near miss, such as a ladder slipping without anyone falling, in a nursery?

  1. It is only needed if a worker is injured
  2. It is used mainly to discipline the worker involved
  3. It has no value unless property is damaged
  4. It allows hazards to be corrected before a serious injury occurs Correct answer.

Explanation

Near misses reveal hazards that could cause real injuries, so reporting them allows controls to be improved before harm occurs. A reporting culture depends on workers feeling safe to report without blame.

Question 8Workplace safety and environmental sustainability in horticulture

A worker must lift heavy bagged potting mix repeatedly. Which approach best applies safe manual handling principles?

  1. Keep the load close to the body, bend the knees and avoid twisting Correct answer.
  2. Twist the torso while lifting to move faster
  3. Bend the back and keep legs straight
  4. Lift with straight arms extended away from the body

Explanation

Keeping the load close, bending the knees and avoiding twisting reduces strain on the spine. Good manual handling technique, plus mechanical aids where possible, lowers the risk of musculoskeletal injury.

Question 9Workplace safety and environmental sustainability in horticulture

What is the main purpose of a risk assessment before starting a tree-pruning task near powerlines?

  1. To replace the need for any supervision on site
  2. To confirm the client's preferred pruning style
  3. To identify hazards and decide on controls before work begins Correct answer.
  4. To record the number of hours each worker will be paid

Explanation

A risk assessment identifies hazards, evaluates the likelihood and consequence of harm, and determines controls before work starts. Near powerlines this is essential to decide on exclusion zones, isolation or specialist assistance.

Question 10Workplace safety and environmental sustainability in horticulture

Which practice best conserves water in an irrigation system on a horticultural property?

  1. Scheduling irrigation based on soil moisture monitoring and plant needs Correct answer.
  2. Watering every day regardless of rainfall
  3. Running sprinklers at midday during hot weather
  4. Increasing irrigation duration to compensate for leaks

Explanation

Scheduling irrigation using soil moisture data and plant demand delivers water when it is needed, reducing waste and runoff. Fixing leaks and avoiding midday losses also improve efficiency.

Question 11Workplace safety and environmental sustainability in horticulture

A worker notices a frayed electrical lead on a hedge trimmer. What is the correct action?

  1. Ask another worker to hold the lead while trimming
  2. Tag the equipment out of service and report it for repair Correct answer.
  3. Tape the lead and continue using the trimmer
  4. Use the trimmer only for short periods

Explanation

Damaged electrical leads present a risk of electric shock and must be removed from service, tagged and reported. Only a competent person should repair and re-test the equipment before it returns to use.

Question 12Workplace safety and environmental sustainability in horticulture

Which of the following is the most effective way to reduce the environmental impact of chemical use in a horticultural operation?

  1. Using integrated pest management to apply chemicals only when thresholds are reached Correct answer.
  2. Applying chemicals as a routine calendar treatment
  3. Storing chemicals in unlabelled containers for convenience
  4. Increasing chemical rates to guarantee control

Explanation

Integrated pest management combines monitoring, cultural and biological controls with chemicals used only when justified by pest thresholds. This reduces chemical volume, resistance and off-target environmental effects.

Question 13Workplace safety and environmental sustainability in horticulture

What is the correct way to store agricultural chemicals on a horticultural property?

  1. Beside livestock feed for easy access
  2. In unmarked drink bottles in the vehicle
  3. In a locked, ventilated store with bunding and clear labels Correct answer.
  4. On an open shelf in the potting shed

Explanation

Chemicals must be stored in a secure, well-ventilated area with spill containment (bunding), correct labelling and separation from food and feed. This prevents accidental poisoning, theft and environmental contamination.

Question 14Workplace safety and environmental sustainability in horticulture

Why should topsoil be stockpiled and reused during a landscaping project?

  1. It preserves soil structure, biology and seed bank and reduces waste Correct answer.
  2. It makes the site look tidier during construction
  3. It reduces the cost of buying new soil only
  4. It is required by law in every Australian state

Explanation

Topsoil contains valuable organic matter, nutrients and soil biology that take years to develop. Reusing it preserves fertility, reduces waste and lowers the need for imported materials.

Question 15Workplace safety and environmental sustainability in horticulture

A worker is handling a concentrated pesticide and some splashes onto their forearm. What should they do first?

  1. Continue working and wash at the end of the shift
  2. Follow the SDS first aid instructions, usually rinsing the skin with plenty of water Correct answer.
  3. Apply a barrier cream over the affected area
  4. Cover the area with a bandage without rinsing

Explanation

Immediate decontamination is critical, and the SDS gives the product-specific first aid directions, which typically start with thorough rinsing with water. Prompt action limits absorption and injury.

Question 16Workplace safety and environmental sustainability in horticulture

What is the purpose of a site induction for a new worker at a horticultural property?

  1. To assess the worker's productivity on day one
  2. To replace the need for ongoing supervision
  3. To explain site-specific hazards, emergency procedures and safety rules Correct answer.
  4. To teach advanced pruning techniques

Explanation

A site induction informs new workers about the hazards, controls, emergency arrangements and rules specific to that workplace. It is a foundation for safe work, not a substitute for training or supervision.

Question 17Workplace safety and environmental sustainability in horticulture

Which control best reduces the risk of heat stress for workers doing summer field work?

  1. Requiring workers to wear extra layers
  2. Providing shade, cool water, rest breaks and adjusting work timing Correct answer.
  3. Discouraging workers from drinking water during tasks
  4. Scheduling heavy tasks for the hottest part of the day

Explanation

Heat stress is managed through shade, hydration, rest and timing work to avoid peak heat, along with monitoring workers for symptoms. These controls reduce heat load and allow recovery.

Question 18Workplace safety and environmental sustainability in horticulture

What is the main environmental concern with runoff from heavily fertilised nursery beds?

  1. It makes the potting mix too light
  2. It reduces the shelf life of the plants
  3. It increases soil temperature in the beds
  4. Nutrients can enter waterways and cause algal blooms and pollution Correct answer.

Explanation

Excess nitrogen and phosphorus in runoff can reach waterways and trigger algal blooms, oxygen depletion and harm to aquatic life. Careful application rates and buffer zones reduce this risk.

Question 19Workplace safety and environmental sustainability in horticulture

A worker finds a snake near a planting area. What is the safest response?

  1. Kill the snake to remove the hazard
  2. Stop work, keep clear and notify the supervisor to arrange a trained handler Correct answer.
  3. Pick it up with gloved hands
  4. Try to move the snake with a shovel

Explanation

Snakes should be left alone and given space, with work paused until a trained handler or wildlife authority manages the situation. Attempting to handle or kill the snake increases the risk of envenomation.

Question 20Workplace safety and environmental sustainability in horticulture

Which of these is the best example of applying the waste hierarchy in a horticultural business?

  1. Burning all prunings on site
  2. Avoiding excess plant stock, then composting unavoidable green waste Correct answer.
  3. Stockpiling waste indefinitely on the boundary
  4. Sending all green waste to landfill

Explanation

The waste hierarchy prioritises avoiding waste first, then reusing, recycling and recovering before disposal. Reducing over-ordering and composting unavoidable green waste follows this order.

Question 21Workplace safety and environmental sustainability in horticulture

A PCBU wants to reduce the risk of musculoskeletal injury from repetitive potting. Which approach best reflects the hierarchy of control?

  1. Rotate workers between tasks only
  2. Provide training on lifting technique only
  3. Introduce a mechanical pot-filling system to reduce manual handling Correct answer.
  4. Issue back braces to all workers

Explanation

Engineering the task to remove or reduce manual handling ranks above administrative measures and PPE in the hierarchy. Task rotation and training are useful supporting controls but rely more on human behaviour.

Question 22Workplace safety and environmental sustainability in horticulture

A horticultural business wants to demonstrate environmental compliance for its chemical use. Which record-keeping practice best supports this?

  1. Keeping application records including product, rate, date, location, operator and weather Correct answer.
  2. Recording only the total chemical purchased each year
  3. Storing records informally in workers' vehicles
  4. Recording chemical use only when a complaint is received

Explanation

Detailed application records allow traceability, demonstrate compliance with label directions and support review of chemical use over time. They also assist in investigating incidents or residues.

Question 23Workplace safety and environmental sustainability in horticulture

During a risk assessment for a steep revegetation site, a worker identifies erosion risk from runoff. Which control is most appropriate?

  1. Remove all vegetation to improve access
  2. Compact the soil with heavy machinery to seal the surface
  3. Install silt fencing, contour drains and stabilise with groundcover Correct answer.
  4. Increase irrigation on the slope

Explanation

Erosion control uses structures such as silt fencing and contour drains plus vegetation to slow runoff and trap sediment. Stabilising with groundcover protects soil structure and prevents sediment reaching waterways.

Question 24Workplace safety and environmental sustainability in horticulture

A worker is exposed to noise from a chipper that exceeds the exposure standard. Which combination best reflects a compliant noise control approach?

  1. Rotate workers so each spends less time near the chipper
  2. Apply engineering controls where practicable, then hearing protection and audiometric testing Correct answer.
  3. Rely on workers to speak up if the noise is uncomfortable
  4. Provide earmuffs only to new workers

Explanation

Noise must be controlled at the source where practicable, with hearing protection and health monitoring used where exposure remains. Audiometric testing helps detect early hearing loss.

Question 25Plant identification, botany and plant selection

Which plant part is primarily responsible for anchoring a plant in the soil and absorbing water and dissolved minerals?

  1. The leaf
  2. The stem
  3. The flower
  4. The root Correct answer.

Explanation

Roots are the organs specialised for anchorage and for uptake of water and mineral nutrients from the soil solution. They also often store carbohydrates, but their defining horticultural roles are support and absorption. Stems and leaves carry out transport and photosynthesis rather than primary uptake.

Question 26Plant identification, botany and plant selection

A gardener wants a plant that fixes atmospheric nitrogen in symbiosis with soil bacteria. Which plant type should be selected?

  1. A legume such as a clover Correct answer.
  2. A bulb such as a tulip
  3. A grass such as a lawn rye
  4. A conifer such as a pine

Explanation

Legumes form root nodules containing rhizobia that convert atmospheric nitrogen into forms the plant can use. This symbiotic relationship enriches both the plant and, eventually, the surrounding soil. Non-legumes generally lack this nodulating bacterial partnership.

Question 27Plant identification, botany and plant selection

Which term describes a plant that completes its life cycle within a single growing season, germinating from seed, flowering and dying in that year?

  1. Biennial
  2. Perennial
  3. Ephemeral
  4. Annual Correct answer.

Explanation

An annual germinates, grows, flowers, sets seed and dies within one growing season. Its whole life cycle is compressed into that period. Perennials persist for many years, while biennials typically take two seasons to complete their cycle.

Question 28Plant identification, botany and plant selection

Which structure on a leaf allows gas exchange for photosynthesis and respiration?

  1. The cuticle
  2. The stoma Correct answer.
  3. The midrib
  4. The petiole

Explanation

Stomata are pores, usually on the leaf underside, that open and close to regulate the exchange of carbon dioxide, oxygen and water vapour. Guard cells control their aperture in response to light and water status. Other leaf structures provide protection, support or attachment.

Question 29Plant identification, botany and plant selection

Which feature best distinguishes a monocot from a dicot in a typical flowering plant?

  1. Monocots always produce woody secondary growth
  2. Monocots usually have two cotyledons and net leaf veins
  3. Monocots bear seeds enclosed in cones
  4. Monocots usually have one cotyledon and parallel leaf veins Correct answer.

Explanation

Monocotyledons typically have a single seed leaf, parallel-veined leaves and floral parts in threes. Dicotyledons usually have two cotyledons and net-veined leaves. These are general patterns, not universal rules, but they are reliable identification guides.

Question 30Plant identification, botany and plant selection

Which term refers to the practice of choosing plants that suit a site's climate, soil and light so they thrive with minimal intervention?

  1. Pricking out
  2. Right plant, right place Correct answer.
  3. Hardening off
  4. Scarification

Explanation

Matching a plant's requirements to the conditions of the site is the core principle of successful plant selection. It reduces inputs such as water, fertiliser and pest control. The other terms describe propagation or acclimatisation techniques.

Question 31Plant identification, botany and plant selection

Which plant group reproduces by spores rather than by seeds?

  1. Ferns Correct answer.
  2. Conifers
  3. Grasses
  4. Orchids

Explanation

Ferns are seedless vascular plants that reproduce via spores produced in sporangia, usually on the underside of fronds. Conifers, grasses and orchids are seed-bearing plants. This distinction is fundamental to classifying garden plants.

Question 32Plant identification, botany and plant selection

A plant's label states it requires 'full sun'. In horticultural terms, this generally means the plant needs which condition?

  1. Bright indirect light with no direct sun
  2. About six or more hours of direct sunlight daily Correct answer.
  3. Two to three hours of morning sun only
  4. Deep shade for most of the day

Explanation

Full sun commonly denotes at least six hours of direct, unobstructed sunlight each day. This level supports strong photosynthesis and flowering in sun-loving species. Partial sun or shade implies fewer hours or filtered light.

Question 33Plant identification, botany and plant selection

A gardener notices a plant with opposite leaves, square stems and a strong aromatic smell. These features are most characteristic of which plant family?

  1. The rose family (Rosaceae)
  2. The pea family (Fabaceae)
  3. The mint family (Lamiaceae) Correct answer.
  4. The grass family (Poaceae)

Explanation

Opposite leaves, square stems and aromatic oils are classic identifying features of the mint family. Many culinary herbs such as basil, rosemary and sage belong to it. The other families have different combinations of stem and leaf characters.

Question 34Plant identification, botany and plant selection

A soil test shows a pH of 8.2. Which statement best explains why an acid-loving plant such as a rhododendron may perform poorly in this soil?

  1. At high pH plants cannot absorb any water at all
  2. At high pH the soil holds too much water for roots to breathe
  3. At high pH the plant's flowers change colour permanently
  4. At high pH certain nutrients such as iron become less available to the plant Correct answer.

Explanation

Alkaline soils reduce the solubility of several micronutrients, particularly iron, leading to deficiency symptoms such as yellowing between veins. Acid-loving plants evolved in low-pH conditions and struggle when these nutrients are locked up. The effect is about nutrient availability, not water uptake or flower colour.

Question 35Plant identification, botany and plant selection

Which term describes a plant adapted to survive long dry periods by storing water in swollen leaves or stems?

  1. Succulent Correct answer.
  2. Epiphyte
  3. Halophyte
  4. Deciduous

Explanation

Succulents store water in fleshy tissues such as thickened leaves or stems, allowing them to endure drought. This adaptation supports their use in low-water gardens. The other terms describe leaf-shedding, growing on other plants, or salt tolerance.

Question 36Plant identification, botany and plant selection

When selecting a tree for a narrow suburban verge, which growth habit is most appropriate?

  1. A narrow, upright cultivar with a compact canopy Correct answer.
  2. A low groundcover shrub
  3. A wide-spreading shade tree with surface roots
  4. A vigorous vine trained up a trellis

Explanation

Narrow, upright cultivars fit restricted spaces and reduce conflicts with overhead wires, vehicles and pedestrians. Wide-spreading trees with surface roots create clearance and pavement problems. Vines and groundcovers do not provide the required tree form.

Question 37Plant identification, botany and plant selection

Which of these is a reliable vegetative method of propagating a named cultivar so that offspring remain genetically identical to the parent?

  1. Allowing natural cross-pollination
  2. Sowing seed from a mixed planting
  3. Collecting and sowing open-pollinated seed
  4. Taking stem cuttings Correct answer.

Explanation

Vegetative propagation such as cuttings produces clones that retain the cultivar's characteristics. Seed from open-pollinated plants involves recombination and may not breed true. This is why named cultivars are usually propagated asexually.

Question 38Plant identification, botany and plant selection

A leaf has a blade divided into separate leaflets arranged along a central axis. Which term best describes this leaf form?

  1. Pinnately compound Correct answer.
  2. Palmately lobed
  3. Needle-like
  4. Simple

Explanation

A pinnately compound leaf has leaflets arranged along both sides of a central rachis. A simple leaf has an undivided blade. Palmately lobed leaves have incisions radiating from one point rather than separate leaflets along an axis.

Question 39Plant identification, botany and plant selection

Which characteristic of a flower indicates it is likely wind-pollinated rather than insect-pollinated?

  1. Bright colour with landing platforms
  2. Large showy petals and strong scent
  3. Nectar-producing glands and sticky pollen
  4. Small, inconspicuous flowers with abundant lightweight pollen Correct answer.

Explanation

Wind-pollinated flowers invest little in attraction, producing small dull flowers and large quantities of light pollen that drift on air currents. Insect-pollinated flowers instead offer rewards and use colour, scent and sticky pollen to attract vectors. These contrasting strategies are a useful identification clue.

Question 40Plant identification, botany and plant selection

Which term describes plants that retain their leaves and remain green throughout the year?

  1. Dormant
  2. Herbaceous
  3. Evergreen Correct answer.
  4. Deciduous

Explanation

Evergreen plants keep functioning foliage across seasons, shedding and replacing leaves gradually. Deciduous plants lose all their leaves for part of the year. Herbaceous and dormant describe growth form or seasonal state rather than leaf retention.

Question 41Plant identification, botany and plant selection

A plant is described as having a taproot system. Which statement best describes this root type?

  1. A single dominant main root with smaller lateral roots Correct answer.
  2. A dense mat of shallow fibrous roots
  3. Roots that arise from stem tissue above ground
  4. Swollen roots that store water for drought

Explanation

A taproot is a principal downward-growing root from which smaller laterals branch. It anchors deeply and can access water at depth, but it also makes transplanting more difficult. Fibrous, adventitious and storage roots are different categories.

Question 42Plant identification, botany and plant selection

Which feature would most reliably help identify a plant as a conifer rather than a broadleaf tree?

  1. Flowers with petals followed by fleshy fruit
  2. Broad flat leaves that fall in autumn
  3. Seeds borne in cones and usually needle-like or scale-like foliage Correct answer.
  4. Hollow jointed stems with parallel veins

Explanation

Conifers are gymnosperms that bear seeds in cones and typically have needle-like or scale-like leaves. Broad flat leaves with fruit, and hollow jointed stems, belong to other groups. These traits separate conifers from flowering broadleaf trees.

Question 43Plant identification, botany and plant selection

A client wants a low-maintenance garden bed in heavy shade beneath a large tree. Which plant selection is most suitable?

  1. Turf grass requiring six hours of direct sun
  2. Shade-tolerant foliage plants adapted to dry root competition Correct answer.
  3. Drought-tolerant succulents needing full sun
  4. Sun-loving flowering annuals

Explanation

Deep shade under a tree combines low light with competition for water and nutrients from tree roots. Selecting shade-tolerant, root-competition-tolerant plants gives the best chance of establishment. Sun-demanding plants would struggle in these conditions.

Question 44Plant identification, botany and plant selection

Which pair of terms correctly distinguishes a plant's requirement for light from its tolerance of frost?

  1. Frost hardiness determines light requirement directly
  2. Both terms mean the same thing in plant labels
  3. Light requirement determines frost hardiness directly
  4. Light requirement and frost hardiness are separate selection criteria Correct answer.

Explanation

Light requirement describes how much sunlight a plant needs, while frost hardiness describes the minimum temperature it tolerates. They are independent attributes and both must be checked when matching plants to a site. Confusing them can lead to poor plant choices.

Question 45Plant identification, botany and plant selection

Which botanical feature best explains why some plants can survive fire by resprouting from protected buds?

  1. Large fleshy fruits that disperse seed after fire
  2. Shallow fibrous roots concentrated at the surface
  3. A lignotuber or buried bud bank below the soil surface Correct answer.
  4. Broad thin leaves that burn quickly

Explanation

Lignotubers and buried buds are protected from heat and can shoot after fire damages above-ground growth. This adaptation allows rapid recovery in fire-prone landscapes. Surface roots and thin leaves would not provide this protection.

Question 46Plant identification, botany and plant selection

A plant shows yellowing between the veins of young leaves while the veins remain green. Which nutrient deficiency is most likely?

  1. Iron Correct answer.
  2. Potassium
  3. Nitrogen
  4. Phosphorus

Explanation

Interveinal chlorosis on young leaves is a classic sign of iron deficiency, because iron is poorly mobile within the plant and new growth suffers first. Nitrogen and potassium deficiencies usually affect older leaves first, and phosphorus deficiency often causes purplish discolouration.

Question 47Plant identification, botany and plant selection

Which statement best explains why a plant described as 'drought tolerant' may still fail if planted in poorly drained clay soil?

  1. Drought-tolerant plants always need daily watering
  2. Drought tolerance often accompanies sensitivity to waterlogged roots Correct answer.
  3. Clay soil increases the plant's light requirement
  4. Clay soil prevents the plant from flowering in the first year

Explanation

Many drought-tolerant species come from well-drained habitats and their roots rot when waterlogged, so tolerance of dry conditions does not imply tolerance of wet feet. Drainage must be assessed separately from drought hardiness. Light and flowering are unrelated to this failure.

Question 48Plant identification, botany and plant selection

Two plants look similar, but one has alternate leaves and the other has opposite leaves. Which statement best explains why this difference is taxonomically useful?

  1. Leaf arrangement depends on soil fertility
  2. Leaf arrangement changes daily with light direction
  3. Leaf arrangement is identical in all flowering plants
  4. Leaf arrangement is a stable inherited character within many plant groups Correct answer.

Explanation

Leaf arrangement is genetically controlled and consistent within many families and genera, making it a reliable identification key character. It does not fluctuate with day-to-day light or fertility. This is why botanists record it carefully.

Question 49Soil, growing media and plant nutrition

Which soil particle size fraction generally holds the greatest amount of plant-available water?

  1. Coarse sand
  2. Silt Correct answer.
  3. Fine gravel
  4. Gravel

Explanation

Silt particles are intermediate in size and have a moderate surface area, giving good water retention while still releasing much of that water to roots. Sand drains too freely to store much available water, and gravel holds almost none.

Question 50Soil, growing media and plant nutrition

A grower wants to raise soil pH from 5.0 to 6.5 before planting a vegetable crop. Which material is the standard choice?

  1. Ammonium sulfate
  2. Elemental sulfur
  3. Agricultural lime Correct answer.
  4. Aluminium sulfate

Explanation

Agricultural lime, mainly calcium carbonate, neutralises soil acidity and raises pH. Sulfur-containing and ammonium-based products acidify soil over time, so they move pH in the wrong direction for this aim.